Evolutionary and ecological processes are important for modelling the patterns of morphological variation among human populations. Within the ecological dimensions, diet plays a key role in craniofacial variation, due both to the effect of the type and amount of nutrients consumed, on skeletal growth and the localized effect of masticatory forces. In this research, these two dimensions of the diet are discussed, and their influence in the morphological diversification of human populations from southern South America during the late Holocene is evaluated. In particular, the relationship between morphological diversification and dietary diversity in human populations from Central-West Argentina is studied, expanding and reducing the spatial scale to arrive at a better understanding of these processes. Analyses were performed considering three scales: macro-regional (Northwest Argentine, Central-West Argentina, Northern Pampa / Southeast Patagonia), regional (Central-West Argentina) and micro-regional (northern and southern Mendoza).